function I=rgb2double(I)
% RGB2DOUBLE  Convert RGB image to DOUBLE storage class
%   I=RGB2DOUBLE(I) converts the RGB image J from class UINT8, UINT16,
%   SHORT, LOGICAL or DOUBLE to class DOUBLE.
%
%   See RGB2XYZ().

% AUTORIGHTS
% Copyright (C) 2006 Andrea Vedaldi
%       
% This file is part of VLUtil.
% 
% VLUtil is free software; you can redistribute it and/or modify
% it under the terms of the GNU General Public License as published by
% the Free Software Foundation; either version 2, or (at your option)
% any later version.
% 
% This program is distributed in the hope that it will be useful,
% but WITHOUT ANY WARRANTY; without even the implied warranty of
% MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
% GNU General Public License for more details.
% 
% You should have received a copy of the GNU General Public License
% along with this program; if not, write to the Free Software Foundation,
% Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA.

if isa(I,'uint8')
  I = double(I) / 255 ;
elseif isa(I,'uint16') 
  I = double(I) / 65535 ;
elseif isa(I,'logical') || isa(I,'single')
  I = double(I) ;
elseif isa(I,'double')
else
  error(['Storage class ''', class(I), ''' not supported.']) ;
end
